The present invention relates to a gas turbine combustion chamber, more particularly such a combustion chamber having multiple arrays of fuel injectors.
It is known to provide gas turbine engine combustion chambers with two sets of fuel injectors whereby one set, known as the pilot injectors, inject fuel into the combustion chamber during idling and low power engine operation, while the injectors of the other set, known as the take off or main injectors, inject fuel into the combustion chamber during full power, take off, or cruising mode of operation of the engine.
Typically, such sets of fuel injectors are arranged such that all of the injectors of one set, in an annular combustion chamber, are located either radially outwardly, or radially inwardly of all of the injectors of the other set. This arrangement of the sets of fuel injectors causes many drawbacks, one of which is the radial temperature variation of the exhaust gases emanating from the combustion chamber. Often, the pilot fuel injectors are located radially outwardly of the main injectors and, if the pilot injectors alone are operating, the exit temperatures of the combustion gases at the exit of the combustion chamber may vary between 900.degree. -1,800.degree. K. between the radially inner and the radially outer portions of the combustion chamber exhaust. Such temperature variations also cause radial temperature differential between the root and the tip of a gas turbine blade typically located at the exit of the combustion chamber. This radial temperature variation causes a reduction in efficiency of the gas turbine.